The present invention relates to a solid-liquid contact apparatus. More particularly, the present invention relates to a single or multiple fluidized bed contact apparatus which is provided with one or more trays that have a number of inverted frustum-shaped depressions located adjacent to each other (arranged in order), each of said frustum-shaped depressions having an opening at the upper base.
Heretofore, there have been proposed various systems in which particulate material and liquid are brought in countercurrent contact to effect adsorption, absorption or reaction between them. Of these systems, those which are in industrial practice may be divided into a fixed bed system and a fluidized bed system. The fluidized bed system is of more recent origin than the fixed bed system as a system. Moreover, as compared with the fixed bed system, the fluidized bed system has many advantageous points such that, for example, the entire surface of the solid material is effectively used, the reaction is achieved uniformly throughout the fluidized bed without the occurrence of local reaction and, further, the efficiency of the reaction is so outstandingly superior that it is often ten times as efficient as the fixed bed system, a completely continuous operation is possible, and so on. Thus, the fluidized bed system is widely used in various chemical and petrochemical industries, etc. Above all, it is in use an an extremely advantageous system for the continuous treatment of gases or liquids in quantities.
In the fixed bed system, however, as often experienced when particulate material and liquid react, the reaction product or impurities adhere to the particulate material causing bridge formation or agglomeration of the particulate material. In the conventional fluidized bed system also, the motion of the particulate material in the bed is not uniform in most cases. Moreover, the classification by the motion helps create non-uniform portions causing the agglomeration of the particulate material, so that not only does it become impossible to withdraw the particulate material during the operation but, also, partially hampered fluidization brings about channeling or slugging which often has very remarkably adverse effects upon the adsorption, absorption or reaction.
Heretofore, in such a case, in order to overcome these difficulties there has been adopted, for example, a method in which the solid and liquid are brought in contact in a state of continuous mixing by stirring, in which case the particulate material is engaged in incessant movement. Hence, there is almost no occurrence of the bridging and agglomeration of the particulate material. However, the stirred mixing requires a large power and presents problems concerning the operation, such as maintenance of the stirrer, etc. Further, there are a number of other disadvantages. This is so because a semi-continuous process is necessitated in such a system. Thus, two or more sets of apparatus are compelled to be built together, requiring an enormous site area.
It is an object of this invention to provide a novel fluidized contact apparatus in which the above-described disadvantages have been obviated.
It is a further object of this invention to provide the characteristic features of the apparatus of this invention to produce the following excellent effects:
(1) An apparatus of a fluidized bed system for multi-stage continuous treatment;
(2) Since the particulate material is capable of moving as well as being withdrawn in each stage unit, all of the particulate material can be fully used;
(3) The quantity of the particulate material used within the capacity of the reactor can be varied at will. (This stems from the fact that the number of stages, if desired, can be conveniently reduced by keeping as many upper trays as desired empty, as well as the fact that the depth of the fluidized bed can be varied at will within the range of the spacing between the trays.)
(4) Since all the particulate material is uniformly in motion within the fluidized bed, and since the transfer of the particulate material from tray-to-tray is achieved in such a way that all the material is passed through the openings of trays in a short period of time, neither agglomeration nor the residence of particulate material occurs at all;
(5) Slugging, channelling, etc. are not seen during the operation. Other objects will be apparent hereinafter.